- Joined
- Dec 27, 2020
- Messages
- 1
So I currently have a Taig micro-mill, but I'm getting into some bigger parts, heavier cuts, larger holes, etc and it just isn't rigid enough for me. I'd rather stick with a mill which can be moved by a few guys and a minivan rather than one which has to be crated and freighted every time, which is why I'm deciding between the two lightest mills Precision Matthews has to offer. I'm planning on buying the included DRO kit, if that matters.
Reading the manuals, it seems like they have similar spindles/quills (with the 728 being ~1.5x longer), but the 25 has taper-roller bearings while the 728 has angular contact bearings. I don't plan on using the quill as a quill by the way. Is there any difference in runout or other measures of accuracy or vibration between the two?
How big is the difference in rigidity?
It looks like they did a pretty good job on grinding the PM25's ways, and the 728's ways look similar, except for the x-axis saddle which appears to be scraped. Does this cause any sort of actual difference in smoothness or accuracy in any way? Is there any sort of difference in the accuracy of the table surface?
It seems like they both have backlash-adjustable bronze nuts and 10tpi screws. Is there any difference in the accuracy of the screws and nuts?
The Pm-728VT has a 1-shot oiler and oil channels on the z-axis, which is a really nice feature.
Of course there are the minor differences like the rubber way wiper on the 728's y-axis, minor table size/travel differences, transparent spindle guard, and motor speed differences. Is there anything else? I'm not seeing why the 728 costs $1200 more than the 25 for just those differences, $1400 if you count the extra $200 for the 728's DRO.
Reading the manuals, it seems like they have similar spindles/quills (with the 728 being ~1.5x longer), but the 25 has taper-roller bearings while the 728 has angular contact bearings. I don't plan on using the quill as a quill by the way. Is there any difference in runout or other measures of accuracy or vibration between the two?
How big is the difference in rigidity?
It looks like they did a pretty good job on grinding the PM25's ways, and the 728's ways look similar, except for the x-axis saddle which appears to be scraped. Does this cause any sort of actual difference in smoothness or accuracy in any way? Is there any sort of difference in the accuracy of the table surface?
It seems like they both have backlash-adjustable bronze nuts and 10tpi screws. Is there any difference in the accuracy of the screws and nuts?
The Pm-728VT has a 1-shot oiler and oil channels on the z-axis, which is a really nice feature.
Of course there are the minor differences like the rubber way wiper on the 728's y-axis, minor table size/travel differences, transparent spindle guard, and motor speed differences. Is there anything else? I'm not seeing why the 728 costs $1200 more than the 25 for just those differences, $1400 if you count the extra $200 for the 728's DRO.
